228 LOGGING 



them to sway slightly as the loads travel along the cable. The 

 supports are further braced by the cables (24). 



The tramway is designed to carry a sufficient number of 

 trolleys to keep a constant line of logs traveling toward the 

 unloading end and empty trolleys traveling towards the upper 

 end. The logs, however, should be spaced far enough apart so 

 that at no time will two of them be suspended between a given 

 set of intermediate supports. 



A profile of the line of a tramway of this character is shown in 

 Fig. 62c. 



The above system is designed for ready removal from one site 

 to another, the framework (2) being lowered on a flat car for 

 transport. It is a modification of one known as the Bleichert^ 

 which is extensively employed for transporting timber, ores and 

 other products in mountainous regions, in some cases for dis- 

 tances greater than 20 miles. 



A second type, known as the endless cable tramway, has been 

 employed for the transportation of shingle bolts. A tram of this 

 character built in CaHfornia had a f-inch main cable supported 

 at frequent intervals on 16-inch sheave wheels attached to cross- 

 arms fastened on heavy poles. 



The cable was driven by a donkey engine geared to a 6-foot 

 vertical drum around which the cable was wound several times 

 and then passed out over the sheave blocks. About halfway 

 between the two extremities the tramway turned a right angle, 

 the cable passing around two loose drums at this point. 



Shingle blocks were brought to temporary platforms by chutes 

 and were attached by hand to the grips which were fixed at 

 intervals along the cable. The bolts were tripped automatically 

 at the terminus. 



One hundred grips were operated on the line one-half of which 

 were traveling loaded and the remainder returning empty to 

 the loading point. The average output per hour for the tram- 

 way was thirty cords of bolts. 



1 Adolf Bleichert & Co., Leipzig and Wein. For a description of their system 

 see Modeme Transportanlagen im Dienste der Holzgewinnung and Holzindustrie. 

 Centralblatt fiir das gesamte Forstwesen, October, 191 2, pp. 451-460. 



